UK Prime Minister Theresa May has launched a harsh personal attack against Labour leader Jeremy Corybn, calling her main challenger in the upcoming general election “weak, unstable and nonsensical.”

“I am strong and stable, Corbyn is weak and unstable. It’s about who’s going to be Prime Minister,” she told the Mail on Sunday.

May also blasted the opposition leader for what she called his “conflicting” plans for the UK’s withdrawal from the European Union (EU).

“They say conflicting things in the same sentence, let alone an hour or a day or a week afterwards. Jeremy Corbyn can’t even persuade 172 of his MPs to have confidence in him,” she added, before conducting her first campaign interview with BBC ahead of the June 9 vote.

Corbyn has been an outspoken opponent of May’s way of handling of the EU divorce, warning on many occasions that the PM’s “hard Brexit” plan was going to have severe consequences for the country.

May went on to call the Labour leader “nonsensical” and accused him of “floundering.”

She continued the attacks on BBC, telling Andrew Marr that Labour’s plans for Britain “simply do not add up” and would lead to higher taxes.

In a surprise move on April 18, May called a snap election to be held in June in order to bolster her position before going into two years of negotiations with the EU about Britain’s departure from the bloc.

Her critics viewed the decision as an attempt to gain an even stronger majority and force her EU deal upon people without worrying about resistance within Parliament.

Earlier on Sunday, however, polls showed that Corbyn had been able to cut down Tories’ comfortable lead over the past few weeks by as much as 10 points.

A poll by the Sunday Times showed that the Tories had a 13-point lead with 44 percent of the vote. This is while, a YouGov poll from last week had put the lead at 23 percent.

Corbyn has promised to end weapons deals with Saudi Arabia, if he becomes prime minister. May’s government has been providing Saudis with deadly weapons despite the Riyadh regime’s war on Yemen.

Corbyn has also pledged to stop UK airstrikes in Syria and opt for a political solution instead. Unlike May, he has also refused to fully support Britain’s costly nuclear weapons program, known as Trident.